adjoint_lube_source_term.f90

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!
!
! I know this is a stupid naming convention...
! The `lube` aspect came from a paper that attributed this term to out of plane
! stresses based on lubrication theory.
!
! I preffer to think of it as a constraint that penalizes non-binary designs
!
! The term is $K \int_\Omega \frac{1}{2}\chi|\mathbf{u}|^2$
!
! the corresponding adjoint forcing is $K \chi \mathbf{u}$
module adjoint_lube_source_term
  use num_types, only: rp
  use field_list, only: field_list_t
  use json_module, only: json_file
  use source_term, only: source_term_t
  use coefs, only: coef_t
  use field, only: field_t
  use design, only: design_t
  use brinkman_design, only: brinkman_design_t
  use field_math, only: field_addcol3, field_copy, field_cmult
  use scratch_registry, only: neko_scratch_registry
  use mask_ops, only: mask_exterior_const
  use point_zone, only: point_zone_t
  use utils, only: neko_error
  use field_registry, only: neko_field_registry
  implicit none
  private
 
  ! $K \int_\Omega \frac{1}{2}\chi|\mathbf{u}|^2$.
  type, public, extends(source_term_t) :: adjoint_lube_source_term_t
 
     type(field_t), pointer :: u => null()
     type(field_t), pointer :: v => null()
     type(field_t), pointer :: w => null()
     type(field_t), pointer :: chi => null()
     real(kind=rp) :: k
     class(point_zone_t), pointer :: mask => null()
     logical :: if_mask
 
   contains
     procedure, pass(this) :: init => adjoint_lube_source_term_init_from_json
     procedure, pass(this) :: init_from_components => &
          adjoint_lube_source_term_init_from_components
     procedure, pass(this) :: free => adjoint_lube_source_term_free
     procedure, pass(this) :: compute_ => adjoint_lube_source_term_compute
  end type adjoint_lube_source_term_t
 
contains
  subroutine adjoint_lube_source_term_init_from_json(this, json, fields, coef)
    class(adjoint_lube_source_term_t), intent(inout) :: this
    type(json_file), intent(inout) :: json
    type(field_list_t), intent(in), target :: fields
    type(coef_t), intent(in), target :: coef
    ! real(kind=rp), allocatable :: values(:)
    ! real(kind=rp) :: start_time, end_time
 
 
    ! we shouldn't be initializing this from JSON
    ! maybe throw an error?
 
 
  end subroutine adjoint_lube_source_term_init_from_json
 
  subroutine adjoint_lube_source_term_init_from_components(this, &
       f_x, f_y, f_z, design, K, &
       u, v, w, &
       mask, if_mask, &
       coef)
    class(adjoint_lube_source_term_t), intent(inout) :: this
    type(field_t), pointer, intent(in) :: f_x, f_y, f_z
    class(design_t), intent(in), target :: design
    class(point_zone_t), intent(in), target :: mask
    type(coef_t), intent(in) :: coef
    real(kind=rp) :: start_time
    real(kind=rp) :: end_time
    type(field_list_t) :: fields
    logical :: if_mask
    real(kind=rp) :: k
    type(field_t), intent(in), target :: u, v, w
 
    ! I wish you didn't need a start time and end time...
    ! but I'm just going to set a super big number...
    start_time = 0.0_rp
    end_time = 100000000.0_rp
 
    call this%free()
 
    ! this is copying the fluid source term init
    ! We package the fields for the source term to operate on in a field list.
    call fields%init(3)
    call fields%assign(1, f_x)
    call fields%assign(2, f_y)
    call fields%assign(3, f_z)
 
    call this%init_base(fields, coef, start_time, end_time)
 
    ! point everything in the correct places
    ! NOTE!!!
    ! this is the primal!
    this%u => u
    this%v => v
    this%w => w
 
    select type (design)
    type is (brinkman_design_t)
       this%chi => neko_field_registry%get_field("brinkman_amplitude")
    class default
       call neko_error('Unknown design type')
    end select
 
    this%K = k
    this%if_mask = if_mask
    if (this%if_mask) then
       this%mask => mask
    end if
 
  end subroutine adjoint_lube_source_term_init_from_components
 
  subroutine adjoint_lube_source_term_free(this)
    class(adjoint_lube_source_term_t), intent(inout) :: this
 
    call this%free_base()
  end subroutine adjoint_lube_source_term_free
 
  subroutine adjoint_lube_source_term_compute(this, t, tstep)
    class(adjoint_lube_source_term_t), intent(inout) :: this
    real(kind=rp), intent(in) :: t
    integer, intent(in) :: tstep
    type(field_t), pointer :: fu, fv, fw
    type(field_t), pointer :: work
    integer :: temp_indices(1)
 
    fu => this%fields%get_by_index(1)
    fv => this%fields%get_by_index(2)
    fw => this%fields%get_by_index(3)
 
    ! BE SO CAREFUL HERE
    ! It make look the same as the Brinkman term, but it's assumed that
    ! this source term acts on the adjoint, and the u,v,w here come from
    ! the primal
    call neko_scratch_registry%request_field(work, temp_indices(1))
    call field_copy(work, this%chi)
 
    ! scale by K
    call field_cmult(work, this%K)
 
    ! mask
    if (this%if_mask) then
       call mask_exterior_const(work, this%mask, 0.0_rp)
    end if
 
    ! multiple and add the RHS
    call field_addcol3(fu, this%u, work)
    call field_addcol3(fv, this%v, work)
    call field_addcol3(fw, this%w, work)
    call neko_scratch_registry%relinquish_field(temp_indices)
 
  end subroutine adjoint_lube_source_term_compute
 
end module adjoint_lube_source_term